JP2008221661A - Liquid jet head, method for manufacturing liquid jet head, head cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a coating property (a thickness of a film) tends to be insufficient at a portion in the vicinity of the surface (inlet or outlet) of the liquid supply channel because of a surface tension of a material when a liquid contact film is formed on a liquid supply channel which is formed on an actuator substrate by drilling therethrough. <P>SOLUTION: A pentroof 62 having the contact liquid property made of a laminated film constituted of insulation films 11, 13, 22, a tension adjustment film 24 and a sacrifice layer removal hole sealing film 25 is provided on the actuator substrate 10 at a portion of the surface of a liquid supply hole 60 as the liquid supply channel. A contact liquid film 61 is formed on the pentroof 62 and the inner wall of the liquid supply channel 60. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid discharge head, a manufacturing method thereof, a head cartridge, and an image forming apparatus.

  In general, as a printer / fax / copier or an image forming apparatus combining these functions, for example, a liquid ejection apparatus including a recording head composed of a liquid ejection head that ejects liquid droplets of a recording liquid (liquid) is used. While conveying a medium (hereinafter also referred to as “paper”, the material is not limited, and a recording medium, a recording medium, a transfer material, and recording paper are also used synonymously) In some cases, an ink is attached to a sheet to form an image (recording, printing, printing, and printing are also used synonymously).

  The image forming apparatus means an apparatus for forming an image by discharging a liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. The term “not only” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium. Further, the liquid ejection apparatus means an apparatus that ejects liquid from a liquid ejection head, and is not limited to an apparatus that performs image formation.

  Liquid discharge heads include those that use piezoelectric actuators such as electromechanical transducers, those that use thermal actuators that use film boiling as electrothermal transducers, and electrostatic forces that use electrostatic force between the diaphragm and electrodes. There are some that use electric actuators. Among them, heads using electrostatic actuators have advantages over other types of heads in terms of miniaturization, high speed, high density, and power saving. have.

By the way, in the liquid discharge head, in order to prevent the surface in contact with the ink from being eroded by the ink, a liquid contact film (ink resistant film) is formed. For example, a liquid supply path is provided through the substrate (actuator substrate) on which the pressure generating means is formed, and a liquid contact film is formed on the inner wall surface of the liquid supply path or a liquid contact film is formed on the other wall surface of the flow path. There are the following documents that describe this.
JP 2002-264332 A JP 2003-039666 A JP 2001-001515 A JP 2006-044083 A JP 2003-159801 A JP 2003-145751 A

  By the way, in the above-mentioned patent documents and the like, a liquid film is formed by depositing a metal film or a metal oxide film / nitride film on the inner wall surface of the liquid supply path formed through the actuator substrate by a CVD method or a sputtering method. To form.

  On the other hand, as a method for forming a wetted film, a solution containing a material that becomes a wetted film (for example, polybenzoxazole / polyimide) or a precursor thereof is applied by a spray coating method, dipping, etc. Further, there is a method of forming the film by further performing a crosslinking reaction or the like depending on the material.

  This method is low-cost, can form a thick film in a short time, has excellent flatness due to the fluidity of the liquid at the time of coating (can smooth the unevenness of the base), and can be formed at a relatively low temperature or normal temperature. There are advantages such as being able to. Further, when a photosensitive material is used as the material, patterning (excess portions can be easily removed) with a short number of steps.

  However, when a liquid contact film is formed on the liquid supply path formed through the actuator substrate, when the above method is applied, coverage (film thickness) near the surface (entrance / exit) of the liquid supply path due to the surface tension of the material. ) Is likely to be insufficient.

  The present invention has been made in view of the above problems, and a liquid contact film having a sufficient film thickness is formed on the inner wall surface of the liquid supply path that penetrates the substrate of the liquid discharge head, thereby improving the reliability of the head. Another object of the present invention is to improve the reliability of a head cartridge and an image forming apparatus including the liquid discharge head.

  In order to solve the above problems, a liquid discharge head according to the present invention includes a nozzle hole for discharging droplets, a pressure generation chamber having a pressure generation unit communicating with each of the nozzle holes, and a pressure generation unit. At least one of the liquid supply path provided so as to penetrate the substrate and the substrate surface portion of the liquid supply path is provided with a liquid contact ridge, and a liquid contact film is formed on the ridge and the inner wall of the liquid supply path. It was set as the structure.

  Here, the ridge can be formed of a laminated film of a plurality of films. Moreover, it is preferable to be provided in the board | substrate surface part of the both ends of the liquid supply path which a ridge penetrates. Further, the liquid contact film in the liquid supply path may be a photosensitive material.

  The method for manufacturing a liquid discharge head according to the present invention passes through a nozzle hole for discharging droplets, a pressure generation chamber having pressure generation means communicating with each of the nozzle holes, and a substrate on which the pressure generation means is formed. In the method of manufacturing a liquid discharge head having a liquid supply path, the liquid supply path is formed on at least one of the substrate surface portions of the liquid supply path, and then the liquid contact is applied to the ridge and the inner wall of the liquid supply path. A solution containing a film material or a precursor thereof was applied and the solvent was volatilized to form a liquid contact film in the liquid supply path.

  Here, the liquid contact film material or the precursor thereof may be configured to have photosensitivity.

  The head cartridge according to the present invention has a configuration in which the liquid discharge head according to the present invention and a liquid tank that supplies liquid to the liquid discharge head are integrated.

  In the image forming apparatus according to the present invention, the recording head includes the liquid discharge head according to the present invention.

  According to the liquid discharge head according to the present invention and the head cartridge according to the present invention, a heel having liquid contact is provided on at least one of the substrate surface portions of the liquid supply path, and the liquid contact film is formed on the ridge and the inner wall of the liquid supply path. After forming the soot, the liquid contact film in the liquid supply path was formed by a film forming method in which a solution containing a liquid contact film material was applied to the inner wall of the liquid supply path and the solvent was volatilized. Even in this case, it is possible to prevent insufficient coverage (film thickness) near the surface of the liquid supply path (near the entrance / exit), and it is easy to reduce the liquid contact film by such a film formation method. It is possible to form a wetted film that is relatively thick at a cost and flattened the unevenness of the base, improving reliability and reducing costs. The image forming apparatus according to the present invention includes the liquid ejection head according to the present invention, thereby improving the reliability.

  According to the method for manufacturing a liquid discharge head according to the present invention, after forming a heel having liquid contact property on at least one of the substrate surface portions of the liquid supply path, the liquid contact film material or its Since the solution containing the precursor is applied and the solvent is volatilized to form a wetted film in the liquid supply path, the coverage (film thickness) near the surface of the liquid supply path (near the entrance / exit) is insufficient. In addition, it is possible to easily form a liquid contact film that is relatively thick and flattened the unevenness of the base at a low cost, improving the reliability of the head and reducing the cost.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an example of a liquid discharge head according to the first embodiment of the present invention will be described with reference to FIGS. 1 is an exploded perspective view of the liquid discharge head, FIG. 2 is a plan view showing the same in a transparent state, FIG. 3 is a cross-sectional view taken along line Y1-Y1 of FIG. 2, and FIG. 4 is X1 of FIG. FIG. 5 is a sectional explanatory view taken along line X2-X2 in FIG. 2, FIG. 6 is a sectional explanatory view taken along line X3-X3 in FIG. 2, and FIG. 7 is X4-X4 in FIG. It is a section explanatory view which meets a line.

  The liquid discharge head H is of a side shooter type that discharges droplets from nozzles provided on the surface of the substrate. The liquid discharge head H is an actuator substrate 10 that is a first substrate, a flow path substrate 30 that is a second substrate, and a first substrate. The nozzle substrate 40 which is the third substrate is sequentially laminated, and the three substrates 10, 30, 40 are bonded to each other so that the nozzle 41 for discharging the droplets communicates via the nozzle communication path 34. A chamber (pressure generating chamber) 33, a fluid resistance portion 32 for supplying ink to the liquid chamber 33, and a common liquid chamber 31 are formed. A liquid supply path 60 that is a liquid supply path for supplying ink to the common liquid chamber 31 from the outside is formed in the actuator substrate 10 through the actuator substrate 10.

  The actuator substrate 10 includes a vibration plate 20 that forms a variable region including a variable electrode (vibration plate electrode) that forms a part of the wall surface of the liquid 33, and a gap (gap) 14a formed in the vibration plate 20 by sacrificial layer etching. The diaphragm 20 and the fixed electrode 12a constitute an electrostatic actuator corresponding to each liquid chamber 33.

  The flow path substrate 30 to be bonded onto the actuator substrate 10 communicates with, for example, a silicon substrate having a crystal plane orientation (110), a liquid chamber (discharge chamber) 33, and each liquid chamber 33 via a fluid resistance portion 32. The common liquid chamber 31 and the like are formed as groove portions (concave portions). The nozzle substrate 40 bonded onto the flow path substrate 30 is made of nickel having a thickness of 50 μm, for example, and the nozzle 41 can be formed by a known method such as dry or wet etching or laser processing. The actuator substrate 10 and the flow path substrate 30, and the flow path substrate 30 and the nozzle substrate 403 are bonded with an adhesive 56.

  In the droplet discharge head configured as described above, the nozzles that are desired to discharge the recording liquid based on the image data from the control unit (not shown) in a state where each liquid chamber 33 is filled with the recording liquid (ink). A predetermined pulse voltage is applied to the fixed electrode 12a corresponding to 4 by the drive circuit. By applying this voltage, a positive charge is charged on the surface of the fixed electrode 12a, and an attractive action by an electrostatic force acts between the fixed electrode 12a and the diaphragm 20 including the diaphragm electrode. (It is the variable region that actually deforms). Thereby, since the volume of the liquid chamber 33 is expanded, the recording liquid corresponding to the volume flows from the common liquid chamber 31 into the liquid chamber 33 via the fluid resistance portion 32.

  Thereafter, by setting the pulse voltage to the fixed electrode 12a to 0V (stopping the application), the diaphragm 20 bent downward by the electrostatic force returns to its original position due to its own rigidity. As a result, the pressure in the liquid chamber 33 rises rapidly, and a recording liquid droplet is ejected from the nozzle 41 communicating with the liquid chamber 33. Then, by repeating this operation and continuously ejecting the recording liquid from the nozzle 41, an image is formed on a recording medium (paper) disposed facing the liquid droplet ejection head.

  At this time, when a pulse voltage is applied and the diaphragm 20 is attracted, a negative pressure is generated in the liquid chamber 33, and the pressure vibrates at the natural frequency of the liquid chamber 33. The pressure when the pulse voltage is lowered is a combination of the residual pressure vibration generated when the pulse voltage is raised and the pressure generated when the diaphragm 20 is restored. Therefore, in order to eject droplets effectively in the electrostatic liquid ejection head, not only when the diaphragm 20 is restored, but also when the diaphragm 20 is deformed (when bent), the diaphragm 20 is strong. Must be attracted to the fixed electrode side.

Accordingly, details of the actuator substrate 10 in the liquid discharge head H will be described.
An insulating film 11 is formed on the actuator substrate 10, and a fixed electrode 12 a, an electrode extraction portion 12 b, and a spacer portion 12 c are formed on the insulating film 11 by a fixed electrode layer 12 and covered with the insulating film 13. On this insulating film 13, a sacrificial layer remaining portion 14b and a gap 14a formed by etching away the sacrificial layer 14 are formed, and a diaphragm 20 made of a multilayer film is formed on the sacrificial layer 14b.

  The diaphragm 20 has an insulating film 22 formed on the sacrificial layer remaining portion 14 b and the gap 14 a before being removed, and a diaphragm electrode layer 23 serving as a common electrode corresponding to the plurality of nozzles 41 is formed on the insulating film 22. In addition, a stress adjusting film 24, a sacrificial layer removing hole sealing film 25, and a liquid contact film 26 are sequentially laminated on the diaphragm electrode layer 23.

  The electrode lead-out portion 12b of the fixed electrode 12a is connected to the external lead-out electrode 54 via the through-connecting portion 52 and the wiring 53a, and the diaphragm electrode layer 23 is connected to the external lead-out electrode 55 via the wiring 53b. ing.

  Further, a liquid contact ridge 62 is provided on the substrate surface portion of the liquid supply port 60 which is a liquid supply path of the actuator substrate 10, and a liquid contact film 61 is formed on the ridge 62 and the inner wall of the liquid supply path 60. ing. The insulating films 11, 13, and 22, the stress adjusting film 24, and the sacrificial layer removal hole sealing film 25 constituting the collar 62 have ink resistance (liquid contact property).

  As described above, at least one of the substrate surface portions of the liquid supply path is provided with a ridge having wettability, and the liquid contact film is formed on the ridge and the inner wall of the liquid supply path. Even when a wetted film in the liquid supply channel is formed by applying a solution containing a wetted film material to the inner wall of the supply channel and volatilizing the solvent, the coating property near the surface of the liquid supply channel (near the entrance / exit) Insufficient (film thickness) can be prevented, and reliability is improved.

Specific examples will be described below.
First, the configuration of each part of the liquid ejection head is as follows, but is not limited thereto.
Nozzle (channel) pitch: 85 μm,
Thickness of flow path substrate 30: 400 μm
Liquid chamber width / length / height: 70/1260/80 μm, fluid resistance portion width / length: 35/400/80 μm, thickness of flow path substrate wetted film 35: 1.4 μm
Diaphragm width / length: 60/1200 μm

  The material and film thickness of each layer constituting the actuator substrate 10 can be as shown in Table 1. However, the present invention is not limited to this.

Here, the wettability of each part will be described. In this embodiment, each film has sufficient wettability with respect to the liquid, and therefore the liquid resistance will be described here.
A diaphragm wetted film 26 made of polybenzoxazole is formed on the diaphragm 20 on the sacrificial layer removal hole sealing film 25 made of silicon dioxide. On the other hand, a silicon dioxide film (thermal oxide film) is used as the flow path substrate wetted film 35 on the flow path substrate 30. The difference between the wetted films 26 and 35 is due to the difference in the amount of corrosion allowed (the amount of film reduction due to elution into the liquid).

In addition, the ejection liquid (ink) assumed in this example is ink for an ink jet printer (about ph9), and the expected service environment / period is 35 ° C. for 5 years. The amount of corrosion is as follows. It is an estimated value extrapolated from the acceleration test results for 3 weeks.
Polybenzoxazole: hardly corroded (below the measurement limit)
Silicon dioxide: about 0.7 μm.
Silicon: about 5μm

  On the other hand, since the deformation area of the diaphragm 20 has a small thickness and its rigidity affects the characteristics of the actuator, in this embodiment, it is 0.1 μm or less (preferably 0.05 μm or less). Since it is necessary to suppress the amount of corrosion, it is necessary to cover with a diaphragm wetted film 26 made of polybenzoxazole. Of course, this is the case with this embodiment, and for the liquid that does not dissolve the oxide film, a liquid contact film with polybenzoxazole is not necessary. On the other hand, except for the deformation region (diaphragm portion) of the diaphragm 20, the liquid resistance as much as that of the diaphragm portion is not required. For example, in this embodiment, the corrosion amount of silicon dioxide is almost 0.7 μm. There is no effect.

  By the way, for the silicon that is the material of the flow path substrate 30 and the actuator substrate 10, for example, when the partition wall thickness between adjacent channels is not protected by the liquid contact film, the initial thickness is 15 μm in the configuration of this embodiment. After corrosion: The thickness of the partition is significantly reduced by 5μm, resulting in a significant decrease in the rigidity of the partition wall. As a result, adjacent mutual interference becomes a problem (there may be a phenomenon such as peeling of the adhesive part before that) When the width of the fluid resistance part 32 is increased from the initial 35 μm to 45 μm after the corrosion, the discharge efficiency is lowered, and the characteristics are greatly affected. In addition, the amount of corrosion is considerably large, and the influence on the discharge liquid is also produced. Come. Furthermore, when a region where the silicon substrate is exposed and a region where the silicon substrate is not present are mixed, a notch-shaped depression is formed at the boundary, and there is a concern about the adverse effect on the bubble discharge performance. For these reasons, it is necessary to avoid exposing the silicon substrate.

  The feature of the present invention is that at the entrance / exit portion of the liquid supply path 60, as shown in FIG. 8, films having sufficient liquid contact properties (insulating films 11, 13, 22, stress adjusting film 24, sacrificial layer removal hole sealing). (This is a laminated film composed of the stop film 25, but is not limited to this.) A ridge 62 is provided by 70, and the inner wall of the liquid supply path 60 is covered with the liquid supply path liquid contact film 61.

  Here, the overhang amount of the flange 62 was set to 3.0 μm, which is the same as the film thickness of the liquid supply passage liquid contact film 61. As for the thickness of the liquid supply path wetted film 61, the diaphragm wetted film 26 is formed relatively thin in consideration of the rigidity of the diaphragm. While there is no such limitation, since the inner wall of the liquid supply path 60 has irregularities, it is formed thicker than the diaphragm liquid contact film 26 (this smoothes the irregularities and makes the ink flow smooth. ).

  With such a configuration, ink that corrodes the actuator substrate 10 can also be used. In addition, even when the liquid supply path liquid contact film 61 is formed by a method including a step of applying a solution containing the material or a precursor of the material, sufficient coverage in the vicinity of the entrance / exit of the liquid supply path 60 is obtained. Can be secured.

  Then, by forming the liquid supply passage liquid contact film 61 by a method including a step of applying a solution containing the material or a precursor of the material, a thick film can be formed at a low cost in a short time. The fluidity of the liquid is excellent in flatness (can smooth the unevenness of the base), so it is possible to reduce the cost, and even if there is unevenness on the inner wall of the liquid supply path, it should be highly reliable and improve bubble discharge Is possible. In addition, since it can be formed at a relatively low temperature and can be formed at normal pressure, the degree of freedom in the process can be increased (in this embodiment, the film is formed after the formation of the wiring made of aluminum or the like. be able to.). Furthermore, a photosensitive material can be used as the material for the wetted film, and patterning (removing excess portions) can be easily performed with a short number of steps, which can reduce the cost and increase the degree of freedom in the process. It becomes possible.

  That is, as shown in FIG. 9A, when a substrate 71 (such as the above-described silicon substrate) having insufficient liquid contact property is formed on the inner wall of the liquid supply path 61 by CVD, PVD, or thermal oxidation, When the wall surface of the tenth surface is uneven, a larger uneven shape appears on the inner wall surface of the liquid supply port 60, and the film quality near the corners of the unevenness may be deteriorated depending on the film forming method. In addition, there is a problem that a high-temperature process or a process in a vacuum is required, or that special measures are required to remove the liquid contact film 61A attached to an extra portion. On the other hand, such a problem can be solved by adopting a configuration in which the liquid supply path wetted film 61 can be formed by a method including a step of applying a solution containing the material or a precursor of the material. can do.

  Further, as shown in FIG. 9B, a step of applying a liquid supply path wetted film 61 to a liquid supply path 60A not provided with the ridge 60 with a solution containing the material or a precursor of the material. If the method is included, the liquid contact film 61 becomes very thin at the corner 72, and the substrate 71 is corroded when the step breaks. Even if it is thinly coated immediately after the formation of the liquid contact film 61, the film may be reduced in a subsequent process (for example, plasma treatment for improving adhesiveness) and may be cut off. Further, as shown in FIG. 9C, although the film 70 having sufficient liquid contact property on the substrate 71 having insufficient liquid contact property is formed to some extent, the film thickness still obtained is insufficient. It is.

  By using the liquid supply path configuration provided with the ridge according to the present invention, as described above, the problems caused by the configuration and the film forming method described in FIG. 9 can be solved.

  Here, the film 70 having sufficient wettability is a laminated film composed of the insulating films 11, 13, 22, the stress adjustment film 24, and the sacrificial layer removal hole sealing film 25. As described above, there is a slight elution, but there is no problem in characteristics and functions. Of course, it is not necessary to be a laminated film, it is possible to leave only one single layer, and instead of diverting the film formed for other purposes as in this embodiment, In order to form the film, a film having sufficient wettability can be separately formed. Further, the material of the liquid supply path wetted film is also an example, and other materials may be used. Furthermore, although the pressure generating means is an electrostatic actuator, other pressure generating means may be used.

Next, a manufacturing method of the actuator substrate in the first embodiment of the manufacturing method of the liquid discharge head according to the present invention for manufacturing the liquid discharge head of the first embodiment will be described with reference to FIG.
First, as shown in FIG. 10A, an electrostatic actuator is produced on one surface (actuator forming surface) on the actuator substrate 10.

  At this time, in the region where the liquid supply path 60 is formed, the fixed electrode layer 12, the sacrificial layer 14, and the diaphragm electrode layer 23 are removed (all of which are made of polycrystalline silicon and used). This is because the material is easy to elute from the liquid. In the same region, the insulating film 11 on the substrate, the fixed electrode side insulating film 13, the diaphragm side insulating film 22, the stress adjusting film 24, and the sacrificial layer removing hole sealing film 25 are materials that are difficult to elute with respect to the liquid used. For this reason, all of them are left here, but some of them can be removed in advance in order to shorten the etching time for the same region in a later process or for other reasons. Removal of these films and layers can be performed without increasing the number of processes by changing the mask pattern in the process.

  Further, on the surface opposite to the actuator forming surface, the fixed electrode layer 12, the sacrificial layer 14, and the diaphragm electrode layer 23 are removed, and the substrate insulating film 11, the fixed electrode side insulating film 13, and the diaphragm side insulating film 22 are removed. The stress adjusting film 24 and the sacrificial layer removal hole sealing film 25 are all left.

  In this embodiment, each time the fixed electrode layer 12, the sacrificial layer 14, and the diaphragm electrode layer 23 are formed, the actuator surface is protected by the entire resist, and then only the back surface is etched by wet etching. After all the layers described above are formed (the actuator surface patterning process is performed in the middle), it is possible to leave only the substrate insulating film 11 by continuously removing the laminated film leaving only the substrate insulating film 11. It is. It is also possible to form a new wetted film only on the surface opposite to the actuator forming surface after removing all the layers by polishing.

Next, as shown in FIG. 10B, the liquid supply port 60 is formed by the following steps. First, using the resist 81 where the liquid supply port 60 is formed as a mask, the laminated film from the insulating film 11 on the substrate 11 to the sacrificial layer removal hole sealing film 25 is formed by RIE (Reactive Ion etching) using CF ₄ + CHF ₃ plasma. Then, the actuator substrate 10 is etched with a deep silicon etcher using ICP (Inductive Coupled Plasma). Thereafter, the laminated film from the insulating film 11 to the sacrificial layer removal hole sealing film 25 on the substrate on the surface opposite to the actuator formation surface is etched again by RIE using plasma of CF ₄ + CHF ₃ . Here, the silicon deep etcher used a process (so-called Bosch process) in which an etching step using SF ₆ plasma and a sidewall protective film deposition step using C ₄ F ₈ plasma are repeated. Therefore, wavy irregularities called “scallops” corresponding to the steps are formed. The height of the unevenness depends on the processing conditions, but is suppressed to 0.5 μm or less in this embodiment.

  Next, as shown in FIG. 10C, the wall surface of the liquid supply port 60 is retracted by, for example, isotropic etching of silicon by wet etching, so that the insulating film 11 on the substrate or the sacrificial layer removal hole sealing film is retreated. A ridge 62 composed of up to 25 laminated films is formed. The etching amount becomes the overhang amount of the ridge 60, but in this embodiment, the etching amount and the overhang amount are about 3 μm.

  Next, as shown in FIG. 10D, a liquid supply path wetted film 61 made of polybenzoxazole is formed on the inner wall of the liquid supply path 60 by the following steps. Note that the coating amount (coating time) was adjusted so that the thickness of the liquid supply path wetted film 61 was also about 3 μm.

  That is, Step 1: Spray coating a solution containing a photosensitive polybenzoxazole precursor (which becomes alkali-soluble upon exposure (UV irradiation)) from the back side of the substrate 10 (the surface opposite to the actuator formation surface). Apply. At this time, since the material immediately after the application has fluidity, the film is formed around the back side of the ridge 62 by capillary force. Moreover, the unevenness | corrugation of a foundation | substrate is also smoothed by fluidity | liquidity.

  Step 2: The solvent is volatilized by soft baking (120 ° C.-2 minutes, hot plate).

  Step 3: Excess film that has wrapped around the actuator forming surface side by the exposure / development process is removed. That is, only the excess portion is exposed and alkali-soluble by mask exposure, and then only the exposed portion that has become alkali-soluble is removed by dipping in an alkaline aqueous solution (2.38% TMAH aqueous solution).

  Step 4: The precursor is reacted by hard baking (320 ° C. for 30 minutes, oven) to form a polybenzoxazole film. This step is the maximum temperature in the formation of the liquid supply passage liquid contact film 61, and there is no problem if it is performed after the formation of the wiring made of aluminum or the like.

  As described above, a thick film can be formed in a low cost and in a short time by forming the liquid supply path wetted film by a method including a step of applying a solution containing the material or a precursor of the material. It is possible, and it is excellent in flatness due to the fluidity of the liquid at the time of application (because the unevenness of the base can be smoothed), so it is possible to reduce the cost, and even if there is unevenness on the inner wall of the liquid supply path, highly reliable bubble discharge The effect that it becomes possible to improve property is acquired.

  Next, an example of a liquid discharge head according to the second embodiment of the present invention will be described with reference to FIGS. 11 is an exploded perspective view of the liquid ejection head, FIG. 12 is a plan view showing the same in a transparent state, FIG. 13 is a cross-sectional view taken along line Y11-Y11 in FIG. 12, and FIG. 14 is Y12 in FIG. FIG. 15 is a cross-sectional explanatory view taken along line X11-X11 in FIG. 12, FIG. 16 is a cross-sectional explanatory view taken along line X12-X12 in FIG. 12, and FIG. 17 is X13-X13 in FIG. 18 is a cross-sectional explanatory view taken along line X14-X14 in FIG.

  Here, the common liquid chamber 31 is formed on the surface of the actuator substrate 10 opposite to the actuator forming surface, and the liquid supply port 60 of the first embodiment is connected to the individual liquid supply path 160 for each channel. This is different from the first embodiment. The depth of the common liquid chamber 31 is 550 μm, and the width of the liquid supply path 160 is 60 μm × 100 μm (X direction × Y direction). Further, since the common liquid chamber 31 is provided on the actuator substrate 10 side, the wiring 53a and 53b are routed around the fixed electrode 14a and the diaphragm electrode layer 23.

  By arranging the common liquid chamber 31 on the surface (back surface) opposite to the actuator formation surface of the actuator substrate 10 in this way, it becomes easy to increase the number of nozzle rows (however, the nozzle row is 1 in the figure). Only the columns are shown.)

Next, the manufacturing process of the actuator substrate in the second embodiment of the method of manufacturing the liquid discharge head according to the present invention for manufacturing the liquid discharge head of the second embodiment will be described with reference to FIG.
As shown in FIG. 19A, after the common liquid chamber 31 is formed on the surface (back surface) opposite to the actuator formation surface of the actuator substrate 10, the actuator formation surface of the actuator substrate 10 is the same as that of the first embodiment. Thus, an electrostatic actuator is manufactured. The common liquid chamber 31 can be easily formed by, for example, silicon anisotropic etching using an alkaline aqueous solution.

  Thereafter, as shown in FIG. 19B, the liquid supply path 160 is formed by the same steps as in the first embodiment. Unlike the first embodiment, the resist mask pattern is the same for each channel, but the rest is exactly the same. Next, as shown in FIG. 19C, a ridge 62 made of a laminated film from the insulating film 11 on the substrate to the sacrificial layer removal hole sealing film 25 is formed in the liquid supply path 160 by the same method as in the first embodiment. Are formed at an inlet portion (a portion facing the common liquid chamber 31) and an outlet portion (a portion facing the flow path substrate 30). Then, as shown in FIG. 19D, a liquid supply path wetted film 61 made of polybenzoxazole is formed on the inner wall of the liquid supply path 160 in the same steps as in the first embodiment.

  As described above, after the common liquid chamber 31 is first formed on the back surface side of the actuator substrate 10 in the first step, the mask pattern is different, and the others can be manufactured in the same process as the first embodiment. Is possible.

  In this second embodiment, since it was manufactured in the above process, the inner wall of the common liquid chamber 31 is covered with a laminated film of the substrate insulating film 11 or the sacrificial layer removal hole sealing film 25 having sufficient liquid contact properties. Therefore, it was sufficient to form the ridge only at the entrance / exit part of the liquid supply path 160, but it is necessary to cover all the inner walls of the common liquid chamber 31 with the liquid supply path wetted film 61 in another manufacturing process. In this case, it is preferable to form a ridge made of a liquid-contacting film at the boundary portion between the common liquid chamber 31 and the back surface of the actuator substrate 10.

Next, a head cartridge according to the present invention will be described with reference to FIG. FIG. 20 is an explanatory perspective view showing an example of the head cartridge.
The head cartridge 90 is integrally provided with a liquid tank 93 that supplies ink as liquid to a liquid discharge head portion 92 having nozzles 91. Thereby, a tank integrated liquid discharge head can be obtained.

Next, an example of an image forming apparatus including the liquid ejection head according to the present invention will be described with reference to FIGS. FIG. 21 is a schematic configuration diagram for explaining the overall configuration of the mechanism portion of the apparatus, and FIG. 22 is a plan view of a principal portion of the mechanism portion.
This image forming apparatus is a serial type image forming apparatus, and a carriage 233 is slidably held in the main scanning direction by main and sub guide rods 231 and 232 which are guide members horizontally mounted on the left and right side plates 201A and 201B. The main scanning motor that does not perform moving scanning in the direction indicated by the arrow (carriage main scanning direction) via the timing belt.

  The carriage 233 has recording heads 234a and 234b (which are composed of liquid ejection heads according to the present invention for ejecting ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K). When not distinguished, it is referred to as “recording head 234”). A nozzle row composed of a plurality of nozzles is arranged in the sub-scanning direction orthogonal to the main scanning direction, and is mounted with the ink droplet ejection direction facing downward.

  Each of the recording heads 234 has two nozzle rows. One nozzle row of the recording head 234a has black (K) droplets, the other nozzle row has cyan (C) droplets, and the recording head 234b has one nozzle row. One nozzle row ejects magenta (M) droplets, and the other nozzle row ejects yellow (Y) droplets.

  The carriage 233 is equipped with head tanks 235a and 235b (referred to as “head tank 35” when not distinguished) for supplying ink of each color corresponding to the nozzle rows of the recording head 234. The sub tank 235 is supplementarily supplied with ink of each color from the ink cartridge 210 of each color via the supply tube 36 of each color.

  On the other hand, as a paper feeding unit for feeding the paper 242 stacked on the paper stacking unit (pressure plate) 241 of the paper feed tray 202, a half-moon roller (feeding) that separates and feeds the paper 242 one by one from the paper stacking unit 241. A separation pad 244 made of a material having a large coefficient of friction is provided opposite to the sheet roller 243 and the sheet feeding roller 243, and the separation pad 244 is urged toward the sheet feeding roller 243 side.

  In order to feed the sheet 242 fed from the sheet feeding unit to the lower side of the recording head 234, a guide member 245 for guiding the sheet 242, a counter roller 246, a conveyance guide member 247, and a tip pressure roller. And a conveying belt 251 which is a conveying means for electrostatically attracting the fed paper 242 and conveying it at a position facing the recording head 234.

  The conveyor belt 251 is an endless belt, and is configured to wrap around the conveyor roller 252 and the tension roller 253 so as to circulate in the belt conveyance direction (sub-scanning direction). In addition, a charging roller 256 that is a charging unit for charging the surface of the transport belt 251 is provided. The charging roller 256 is disposed so as to come into contact with the surface layer of the conveyor belt 251 and to rotate following the rotation of the conveyor belt 251. The transport belt 251 rotates in the belt transport direction when the transport roller 252 is rotationally driven through timing by a sub-scanning motor (not shown).

  Further, as a paper discharge unit for discharging the paper 242 recorded by the recording head 234, a separation claw 261 for separating the paper 242 from the transport belt 251, a paper discharge roller 262, and a paper discharge roller 263 are provided. A paper discharge tray 203 is provided below the paper discharge roller 262.

  A duplex unit 271 is detachably mounted on the back surface of the apparatus body 1. The duplex unit 271 takes in the paper 242 returned by the reverse rotation of the transport belt 251, reverses it, and feeds it again between the counter roller 246 and the transport belt 251. The upper surface of the duplex unit 271 is a manual feed tray 272.

  Further, a maintenance / recovery mechanism 281 that is a head maintenance / recovery device according to the present invention includes a recovery means for maintaining and recovering the nozzle state of the recording head 234 in the non-printing area on one side of the carriage 233 in the scanning direction. Is arranged. The maintenance / recovery mechanism 281 includes cap members (hereinafter referred to as “caps”) 282a and 282b (hereinafter referred to as “caps 282” when not distinguished) for capping each nozzle surface of the recording head 234, and nozzle surfaces. A wiper blade 283 that is a blade member for wiping the ink, and an empty discharge receiver 284 that receives liquid droplets for discharging the liquid droplets that do not contribute to recording in order to discharge the thickened recording liquid. ing.

  In addition, in the non-printing area on the other side in the scanning direction of the carriage 233, the liquid that receives liquid droplets when performing idle ejection that ejects liquid droplets that do not contribute to recording in order to discharge the recording liquid thickened during recording or the like. An ink recovery unit (empty discharge receiver) 288 that is a recovery container is disposed, and the ink recovery unit 288 includes an opening 289 along the nozzle row direction of the recording head 234 and the like.

  In this image forming apparatus configured as described above, the sheets 242 are separated and fed one by one from the sheet feeding tray 202, and the sheet 242 fed substantially vertically upward is guided by the guide 245, and is conveyed to the conveyor belt 251 and the counter. It is sandwiched between the rollers 246 and conveyed, and further, the leading end is guided by the conveying guide 237 and pressed against the conveying belt 251 by the leading end pressing roller 249, and the conveying direction is changed by approximately 90 °.

  At this time, a positive output and a negative output are alternately applied to the charging roller 256, that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 251 alternates, that is, in the sub-scanning direction that is the circumferential direction. , Plus and minus are alternately charged in a band shape with a predetermined width. When the sheet 242 is fed onto the conveyance belt 251 charged alternately with plus and minus, the sheet 242 is attracted to the conveyance belt 251, and the sheet 242 is conveyed in the sub scanning direction by the circumferential movement of the conveyance belt 251.

  Therefore, by driving the recording head 234 according to the image signal while moving the carriage 233, ink droplets are ejected onto the stopped paper 242 to record one line, and after the paper 242 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 242 has reached the recording area, the recording operation is finished and the paper 242 is discharged onto the paper discharge tray 203.

  Since this image forming apparatus is equipped with the liquid discharge head according to the present invention, the reliability is improved and a high-quality image can be stably formed.

  In the above embodiment, the image forming apparatus having a printer configuration is described. However, the present invention is not limited to this, and the present invention can be applied to an image forming apparatus such as a printer / fax / copier multifunction machine. The present invention can also be applied to a liquid discharge head or an image forming apparatus that discharges a DNA sample, a resist, a pattern material, or the like. The electrostatic actuators that make up the liquid discharge head are not only liquid discharge heads, but also micro pumps and optical devices (light modulation devices), as well as micro switches (micro relays) and multi-optical lens actuators (light Switch), micro flow meter, pressure sensor, and the like.

FIG. 3 is an exploded perspective view illustrating a first embodiment of a liquid discharge head according to the present invention. FIG. 3 is an explanatory plan view showing the same head in a transmissive state. FIG. 3 is a cross-sectional explanatory view taken along line Y1-Y1 of FIG. FIG. 3 is a cross-sectional explanatory view taken along line X1-X1 in FIG. FIG. 3 is a cross-sectional explanatory view taken along line X2-X2 of FIG. FIG. 3 is a cross-sectional explanatory view taken along line X3-X3 in FIG. FIG. 3 is a cross-sectional explanatory view taken along line X4-X4 of FIG. FIG. 4 is an enlarged explanatory view of a main part of FIG. 3. It is principal part expansion explanatory drawing which shows a comparative example. It is sectional explanatory drawing with which it uses for description of the manufacturing process of the actuator substrate in 1st Embodiment of the manufacturing method of this invention. FIG. 6 is an exploded perspective view showing a second embodiment of the liquid ejection head of the present invention. It is a plane explanatory view similarly shown in a transmission state. FIG. 13 is an explanatory sectional view taken along line Y11-Y11 in FIG. FIG. 13 is an explanatory cross-sectional view taken along line Y12-Y12 in FIG. FIG. 13 is an explanatory sectional view taken along line X11-X11 in FIG. It is sectional explanatory drawing which follows the X12-X12 line | wire of FIG. FIG. 13 is an explanatory sectional view taken along line X13-X13 in FIG. It is sectional explanatory drawing which follows the X14-X14 line | wire of FIG. It is sectional explanatory drawing with which it uses for description of the manufacturing process of the actuator substrate in 2nd Embodiment of the manufacturing method of this invention. It is a perspective explanatory view showing an example of a head cartridge according to the present invention. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present invention. Similarly it is principal part plane explanatory drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Actuator board | substrate 12a ... Fixed electrode 14a ... Air gap (gap)
20 ... Diaphragm 30 ... Flow path substrate 31 ... Common liquid chamber 33 ... Liquid chamber (pressure generation chamber)
40 ... Nozzle plate 41 ... Nozzle 60 ... Liquid supply port (liquid supply path)
61 ... Liquid contact film 62 ... 庇 160 ... Liquid supply path

Claims (8)

Nozzle holes for discharging droplets;
A pressure generating chamber provided with pressure generating means communicating with each of the nozzle holes;
A liquid supply path provided so as to penetrate the substrate on which the pressure generating means is formed;
A liquid discharge head comprising: a liquid-contacting ridge provided on at least one of the substrate surface portions of the liquid supply path; and a liquid-contact film formed on the ridge and an inner wall of the liquid supply path.   The liquid discharge head according to claim 1, wherein the ridge is formed of a laminated film of a plurality of films.   3. The liquid discharge head according to claim 1, wherein the liquid discharge head is provided on a substrate surface portion at both ends of the liquid supply path through which the ridge penetrates.   4. The liquid discharge head according to claim 1, wherein the liquid contact film in the liquid supply path is a photosensitive material. A liquid having a nozzle hole for discharging droplets, a pressure generating chamber having pressure generating means communicating with each of the nozzle holes, and a liquid supply path provided so as to penetrate the substrate on which the pressure generating means is formed. In the manufacturing method of the discharge head,
After forming a wetted soot on at least one of the substrate surface portions of the liquid supply path, a solution containing a wetted film material or a precursor thereof is applied to the soot and the inner wall of the liquid supply path to volatilize the solvent. And a liquid contact film in the liquid supply path is formed.   6. The method of manufacturing a liquid discharge head according to claim 5, wherein the liquid contact film material or a precursor thereof has photosensitivity.   5. A head cartridge, wherein the liquid discharge head according to claim 1 and a liquid tank for supplying liquid to the liquid discharge head are integrated.   5. An image forming apparatus comprising a recording head composed of a liquid ejecting head for ejecting liquid droplets, wherein the recording head is composed of the liquid ejecting head according to any one of claims 1 to 4. apparatus.

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